A squeegee unit of this type is known in practice in various designs. A design which is in widespread use is one in which the squeegee comprises an elongate metal squeegee blade and an edge strip which is fitted to it in the longitudinal direction, forms the squeegee edge and is made from an elastomer material with a hardness which is such that unevenness in the material to be printed can be overcome. The squeegee blade is clamped in the squeegee holder at the opposite longitudinal side from the squeegee edge. The squeegee blade is resilient and is responsible for positioning the squeegee edge and transmitting force from the squeegee holder to the squeegee edge. During operation of a rotary screen-printing device in which the squeegee unit is mounted, the squeegee holder is positioned in such a manner that the squeegee edge is pressed onto the inner side of the cylindrical screen with a defined prestress, the resilient squeegee blade being deformed slightly. In a rotary screen-printing device, an element which provides a counterpressure, for example a counterpressure roll, is present opposite the squeegee edge on the outer side of the cylindrical screen.
The known squeegee unit has the drawback that in a situation in which the squeegee edge is pressed onto the inner side of the cylindrical screen, the counterpressure disappears, the squeegee edge can excessively deform the cylindrical screen and thereby damage it. Examples in which the counterpressure may disappear are:    when a rotary screen-printing device is integrated in an intaglio printing or offset sheet-fed rotary printing machine, the counterpressure roll of which in the axial direction has a gap for retaining/positioning the substrate which is to be printed. The counterpressure disappears at the location of the gap.    when a rotary screen-printing device is integrated in a semi-rotary flexographic, letterpress or offset printing press, in which case the substrate web which is to be printed has to be free from contact from any printing system during part of the printing cycle so that it can be positioned for the next printing cycle, but at the start of the new printing cycle all the squeegee settings required have to be available immediately.    in the case of a rotary screen-printing device for treating (printing) discrete substrates with a considerable thickness, as described, for example, in EP 0 974 458 A1. In this case, a counterpressure roll does not necessarily have to be present. The substrates themselves, lying on a conveyor system, supply the counterpressure. The counterpressure disappears at the edges of the substrates.